Renovation of children's room - split one window into two windows?

I had expected the following dimensions. The long edge is 8.01 m. If I position the wall as follows, the lower room then measures 3 m x 4.075 m there. The 3 m (green line) results from the specified dimensions on the left (0.695 - 0.3) + 1.51 + 1.365 - orange new construction wall.

The middle window starts 4.25 m measured from the bottom of the plan. <-- How do you arrive at 4.25 m? I must have a flaw in my thinking here.

Are we thinking the same thing, or do I have a flaw in my thinking somewhere? I can't

No, Biber is wrong: the entire length of the interior is 8.01. Biber must have calculated the outer wall incorrectly somehow (subtract 30cm at the bottom and top). Both rooms are separated by 12 cm. The partition wall will then have to be placed in the middle of one of the windows.

Regards

You are right, it is 8.01 m (total length of the entire room), no idea what I calculated. And then I actually mixed up left and right or window and door. I better go to the garden ... (as soon as it gets light). Sorry for causing confusion here ...